This invention relates to medical devices, such as endoprostheses.
Medical endoprostheses, such as stents, can be placed within the body to perform a function, such as maintaining open a body lumen, for example, a passageway occluded by a tumor or a blood vessel restricted by plaque. Other endoprostheses such as stent-grafts, or covered stents, can be used to substitute for or reinforce a lumen, such as the aorta or other blood vessels that have been weakened, e.g., by an aneurysm.
Endoprostheses can be delivered inside the body by a catheter that supports an endoprosthesis in a compacted or reduced-size form as the endoprosthesis is transported to a desired site. Upon reaching the site, the endoprosthesis is expanded, for example, so that it contacts the walls of the lumen.
The expansion mechanism may include forcing the endoprosthesis to expand radially. For example, the expansion mechanism can include the catheter carrying a balloon, which carries the endoprosthesis. The balloon can be inflated so as to deform and fix the expanded endoprosthesis at a predetermined position in contact with the lumen wall. The balloon can then be deflated, and the catheter removed.
This invention relates to medical devices, such as endoprostheses.
In one aspect, the invention features a medical device including a catheter having an expandable balloon, an expandable endoprosthesis positioned on the balloon, and an expandable sleeve. The endoprosthesis has a first end and a second end, and the expandable sleeve extends over an end of the endoprosthesis and a portion of the balloon adjacent to the end of the endoprosthesis. The sleeve is configured to separate into a plurality of portions.
Embodiments of aspects of the invention may include one or more of the following features. The endoprosthesis includes a stent. The endoprosthesis has an outer surface, and the sleeve extends over or covers the outer surface of the endoprosthesis. The sleeve extends over the first and second ends of the endoprosthesis.
The balloon can include a tapered portion, and the sleeve can be attached to the tapered portion. The balloon can include a sleeve portion, and the sleeve can be attached to the sleeve portion. The sleeve can be attached to the catheter.
The sleeve can be a tubular member. The sleeve can be configured to separate into at least three portions. The sleeve can include a polymer, such as a silicone, a polyurethane, a latex, and a polyether amide. The sleeve can include a therapeutic agent. The sleeve can have a surface defining an opening. The sleeve can be configured to separate at a predetermined pressure. The sleeve can be configured to separate at a predetermined level of expansion of the balloon. The sleeve can include portions configured to move away from the endoprosthesis after the sleeve separates.
In another aspect, the invention features a medical device having a catheter including an expandable balloon, a stent positioned over the balloon, the stent having an outer surface, a first end, and a second end, and a sleeve extending over the outer surface and the first and second ends of the stent, the sleeve further extending over portions of the balloon adjacent to the ends of the stent. The sleeve includes a separation portion.
Embodiments of aspects of the invention may include one or more of the following features. The sleeve includes a polymer. The sleeve includes a therapeutic agent. The sleeve is attached to the catheter. The sleeve is a tubular member. The sleeve covers the outer surface of the stent.
The balloon can have a tapered portion, and the sleeve can be attached to the tapered portion. The balloon can have a sleeve portion, and the sleeve can be attached to the sleeve portion.
The separation portion can be perforated. The separation portion can have a thickness less than a thickness of the balloon. The separation portion can be over the stent and/or over the balloon.
The device can include a plurality of separation portions. The separation portions can be asymmetrically positioned along the catheter. The separation portions can be configured to separate under different or similar conditions.
In another aspect, the invention features a method including positioning a medical device having a catheter having an expandable balloon, an expandable endoprosthesis positioned on the balloon, the endoprosthesis having a first end and a second end, and an expandable sleeve extending over an end of the endoprosthesis and a portion of the balloon adjacent to the end of the endoprosthesis; and separating the sleeve into a plurality of portions.
Embodiments of aspects of the invention may include one or more of the following features. Separating the sleeve includes expanding the sleeve. The method includes separating the sleeve sequentially. The method includes separating the sleeve into three portions substantially simultaneously. The method includes separating the endoprosthesis and the sleeve from the catheter. The sleeve has an outer surface defining an opening, and the method further includes aligning the opening with an opening of a body lumen.
Embodiments may have one or more of the following advantages. The sleeve can prevent the ends of the endoprosthesis from contacting, e.g., snagging or cutting, the body lumen, thereby reducing damage to the lumen. The sleeve can have a smooth, relatively low friction outer surface to provide the medical device with good insertion and tracking during use. The sleeve can include a drug that is released in the body lumen after the endoprosthesis and sleeve are delivered. Manufacturing of the sleeve can be relatively simple, with relatively low risk of contamination or damage to the sleeve.
Other features and advantages of the invention will be apparent from the description of the preferred embodiments thereof and from the claims.